Micrometer depth gauge



Aug. 4, 1931. P. N; HANSEN MICOMETER DEPTH GAUGE Filed April 23. 192s Z weg auna,

Patented Aug. 4, 1931 PETER 1v,- Her-SEN, 0F

PATENT EMERSON, .NEBRASKA amenant DEHH- GAUGE Application filed April 2 3,

My invention relates to micrometer depth gauges, or gauges of the class wherein the base or frame of the instrument is engaged with the surface trom which measurement J; is to be made, and the distance to be measured fromsaid basesurfaceis indicated by the extension therefrom of a spindle under control of a micrometer screw. In ordinary micrometer calipers tor outside and inside measurements, the instrument is read by reference to a scale graduated on a sleeve carried by the frame ot the instrument, said sleeve being progressively uncovered by the thimble as the measure is increased, sothat the exposed portion of the scale represents the distance vor reading desired. In micrometer depth gauges as usually con.- structed, the relation of the graduated sleeve and the thimble is the reverse of that employed in calipers, in that the sleeve is progressively covered by the thimble as the Ameasure is increased, and consequently the desired reading is indicated by the covered portion instead of the uncovered or exposed portion of the scale on the sleeve. This reversed relation of the sleeve and thirnble tends to confuse the workman, and to cause errors in reading the indications ci" such depth gauges. It isthe object of my invention to provide a micrometer. vdepth gauge wherein the indication or reading of the desired measurement is eilected inthe same manner as in micrometer calipers, or in which the exposed portion ot the scale graduated on the sleeve indicates the measurement to be read, whereby confusion or error in reading the indications of the instrument may be avoided.

In the accompanying drawings Fig. 1 a longitudinal section of an instrument ern- ]oodying my invention, the parts being shown the position for maximum extension of the spindle from the base surface, Fig. 2 is a side elevation of the same, Fig, 3 is an end elevation of the same, Fig. i is a longitudinal section of a sliOhtly modified ormot` the instrument, Fig. 5 is an end elevation of the same, showing the spindle fully retracted relative to the base surface,

192,8. V'Serial No. 272,218.

and Fig. 6 is ya transverse section on the line -6-6 of Fig.

Referring first to the structure shown in Figs. 1, 2 and 3, I provide a base 10 having at the central portion thereof the internally threaded boss 11 into which is screwed the lower end of an upright trame comprising a tubular lower portion 12, an annular headportion 18, and an intermediate open portion formed by a pair of diametrically opposite bars 14 integral with the portions 12 and 13. Into the threaded opening through the head 18 is screwed the sleeve 15 which has at its upper end a flange 16 engaging the upper side Vof the head 18. The body of the sleeve vextends down through the open portion of the trame between the bars 14, and upon one side of the sleeve is marked the usual scale 17, with numbered graduation marks for each tenth of an inch, and intermediate Lin-numbered marks for each twenty-five thousandths of an inch. The lower portion lof the sleeve is provided with an internal ythread forming the micrometernut which is engaged by the screw 18, the latter being tubular and having an n nthreaded stem-portion 19 extending slidably through the upper end of the sleeve.

rlhe upper end ot the tubular screw-stein -19 is conically beveled, and adjacent to said beveled end the stem is threaded to receive the clamp-nut 20. The threaded and beveled end of the stern is slitted or kerted longitudinally, whereby to term a collet for 'clampingthe spindle 21, which extends slidably through the stem and the screw 18, and projectsthrongh an opening in the base 10, as shown. The collet-end of the stem 19 has small inwardly extending lugs 22 adapted to ent-er grooves 23 in the spindle, whereby to assure the clamping of the latter in exact relations to the screw. The thimble 24 is iixedly united or integral with the lower portion of the screw 18, and -extends upwardly about the screw toinclose the same and the lower portion of the sleeve 15, over which it lits slidably. The upper end ot the thimble is conically beveled and is graduated in the usual-manner tor indicating partial or fractional rotation of the same, cor- (ffl 2 Lei arlresponding to thousandths of an inch vance ot the screw. The lnurled settingcollar 25 is formed integrally with the thimble, and moves in the open portion ot the trame between the bars 14, the sides ot the collar being thus exposed for engagement between the thumb and finger ot the user, iior rotating the thimble and Screw as required in the operation of the instrument.

it the positions et the parts shown in Figs. 1, 2 and 3, the spindle is at themaximum extension from the base-surface, and the scale 17 on the sleeve is fully uncovered or exposed. By suitable rotation o the thimble, screw and spindle, `he latter is retracted or withdrawn into the base, and the sleeve is progressively covered by the thimble, until at the limit of the retracting movement the end or" the spindle is lush with the base surface and the end ot the thiinble is in register with the zero (O) niark of the scale 17 on the sleeve, said scale being then entirely covered by the thiinble. 1t will thus be seen that at all times the amount et extension ot the spindle from the base suriace will be the saine as the length oi the exposed or uncovered portion ot the scale 17 on the sleeve, and the reading ot the instrument will correspond with the reading ordinary micrometer calipers, whereby the user tamili ar with the latter will not be confused and caused to err in the reading ot the depth gauge.

1n the modified structure represented in Figs. 4, 5 and 6, the setting-collar is omitted from the thiinble 24, and a collar 25 is mounted revolubly in the head 13 of the trame, said collar being retained in the head by means et small screws 27 extending through the sides ot the head and having inner end-portions entering a groove in the collar, as shown in Fig. 6. The screw-stein 19 passes slidably through the bore ot the collar 25, and said stem 19 has a longitudinal groove or lreyway 2S into which is extended a lug 29 termed in the bore ot the collar as shown in Fig. 6. The screw-stem 19', screw 18, thimble 24U, and spindle 21 may thus be rotated by turning the collar 25 within the head 13. The upper end ot the stem 19 is provided with a clamp-nut and inwardly extended lugs 22', said portion ot the stem being lerted or siitted to torni a collet, as in the rst described form of the instrument. The sleeve 1 5 is screwed into the head 13 from the lower` side thereof', the flange 16 engaging the lower side ot the head, and otherwise said sleeve 15 is the saine as the sleeve 15. It will be seen that in the modified structure the open portion of the traine, termed by the bars 141/, may be made narrower than the frame ot the first instrument, due to the omission ot the setting-collar from the thimble. The operation ot the moditied 'instrument is the same as the lirst, except that by rotation ot the setting-collar its longitudinal relation to the :trame is not changed, while the setting-collar 25, being integral with the thimble, moves longitudinally when rotated.

Now, having described my invention, what I claim and desire to secure by Letters Patent is:

1. 1n a micrometer depth gauge, a 'trame having an annular head, a tubular base portion and bars connecting the head with the base portion; a sleeve secured to the annular head and extending into the space intermediate the head and base, said sleeve having an internal thread, a screw engaged with said thread and extending through the sleeve, a thimble ixedly connected with said screw and extending about said sleeve, and a spindle carried by the screw and extending through the base portion of the iframe.

2. A micrometer depth gauge, comprising a trame having a head, a base and an open intermediate portion; an internally threaded sleeve secured to the head of the traine and extending into the open intermediate portion thereof and having a graduated scale, a tubular screw engaging the internal thread of said sleeve, said screw having a stem portion extending through the upper end of the sleeve and provided with a collet, a spindle secured to said stem by said collet and extending through the stem and the screw and adapted to project from the base of the frame, and a thiinble lixedly associated with said screw and having a graduated end portion arranged 'for coaction with the scale graduated on said sleeve, the thimble and'sleeve being associated to expose portions of said scale corresponding to the projection et the spindle from the base.

3. In a micrometer depth gauge, the combination with a sleeve having a longitudinal scale graduated thereon, a screw having threaded connection with said sleeve, a thimble fixedly associated with said screw and movable about the sleeve during rotation o1 the screw thereir and a spindle connected with said screw; of a trame having a head to which said sleeve is secured and having a tubular base portion toward which said sleeve extends from the head, the portion of the frame intermediate said head and base having openings to expose the scale on the sleeve, the spindle carried by the screw being adapted tor extension through the base portion of the trame, and the thimble being so related to the sleeve as to uncover and expose a portion ot the scale thereon corresponding with the distance to which the spindle is extended from the base surtace.

PETER N. HANSEN. 

